


Magic+Science=Alchemy

by Widow_Spyder



Series: Sengen Week 2 [5]
Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Alternate Universe - Modern Setting, Alternate Universe - Modern with Magic, Domestic Fluff, First Meetings, Fluff, Fluffy Ending, M/M, Magic, Minor Injuries, Sengen week, day 5 fantasy ay, sengen, sengen week 2020
Language: English
Status: Completed
Published: 2021-01-03
Updated: 2021-01-03
Packaged: 2021-03-12 21:09:14
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,833
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28516935
Author URL: https://archiveofourown.org/users/Widow_Spyder/pseuds/Widow_Spyder
Summary: Needless to say, the day Gen gets a weak sounding knock on his door, it surprises him. The magical community had been trying to recruit him for years in various ways, such as negotiating and attacking to take in forcefully. But never have they just knocked on his door, which either meant that the person at his door was just a weary traveler, or it was a trap to lure him into a false sense of security.
Relationships: Asagiri Gen/Ishigami Senkuu
Series: Sengen Week 2 [5]
Series URL: https://archiveofourown.org/series/2080821
Comments: 10
Kudos: 81
Collections: Sengen Week 2020-2021





	Magic+Science=Alchemy

**Author's Note:**

> *edit* the coding is not working in this fic so enjoy the story breakers at the front instead of the middle T-T

Needless to say, the day Gen gets a weak sounding knock on his door, it surprises him. The magical community had been trying to recruit him for years in various ways, such as negotiating and attacking to take in forcefully. But never have they just knocked on his door, which either meant that the person at his door was just a weary traveler, or it was a trap to lure him into a false sense of security. 

So Gen stays put in his kitchen, crouched low and waiting. The knocks increased, banging loud on the wood for a few minutes until everything went silent again. For a second, Gen was sure whoever it was had left. 

Until a rock flew through the window on the door, smashing glass and creating a mess. In his surprise, Gen stood up and accidentally knocked a pan over, which clattered to the floor and effectively halted the being outside from what it was doing. 

Tentatively a voice rang out, muffled from behind his door. “Hello? So there is someone who lives here.”

“And what if there is?” Gen hesitantly asked back. What he didn’t expect was the voice answering him from so low to the ground. 

“Then you probably have some spare stuff you don’t need, right?”

“Spare stuff?” Gen wondered out loud. He was thoroughly confused as he took a chance and opened the door only to see a kid with strange hair, covered in leaves outside his house. “Who’re you?”

“Ishigami Senku.” The child, ‘Senku,’ answered. “And you are?”

“Asagiri Gen.” 

Senku looked him over, an amused smile creeping onto his face. “Why are you dressed like a witch?”

Gen’s eyebrow raised. “Why are you dressed in leaves?”

“Fair point. Can I come in?” Senku asked, gesturing towards the inside of his house. 

Gen shrugged and moved to the side to let him in. From what Gen could tell, the child ‘Senku’ didn’t have a magical aura or bad energy around him, so for the time being, it should’ve been safe to let him in. The vines and leaves covering him snapped and crunched as he walked, making Gen cringe.

“Oh, here, some clothes, so you don’t drag leaves on my carpet.” Gen said, stopping Senku where he stood as he went to the closest and brought out some old clothes. They were too big for his tiny body, so Gen cast a shrinking spell to make them smaller, surprised when the kid gasped, his eyes so wide they looked like they’d burst out of his skull. 

“What the-” Senku stammered, looking fit to shake apart at the mundane display. 

“What? Never seen magic before?” Gen teased, confused at his reaction. 

“Not once, no.”

_Wait…_ “Wha-”

“Does it come naturally to you? I guess this means that only half of the world was petrified then. So that must be how you got these ‘powers’ right?” Senku started rambling. “It’s been almost 4,000 years, so the green light must’ve had properties to make you immortal and grant you magic, right? Does it differ from person to person? What is it like casting spells? Is it a mental thing? Oh! Can you-”

“Shh.” Gen hushed, desperately placing his hand over Senku’s mouth to quiet him. “Slow down, please. Are you telling me you were there when the green light petrified the world?”

“Yep. I was a statue until a week ago. You’re the first person I’ve seen since.”

“Right…” Gen nodded, shocked at how calm the kid said it. _No one had reportedly broken out of petrification._ “I’d like to assess you with my magic if that’s alright?”

Senku shrugged. “Sure, I don’t have anything to hide.”

“Alright.” Gen gestured towards the spare bed in his room for Senku to lay on. “Hold still, please.” Gen requested as Senku laid back and closed his eyes. Gen concentrated as he placed his hand gently on top of Senku’s forehead, closing his own eyes as the swirl of Senku’s memories played in his head. 

_He can see their old world. Back when everything was normal. When entire cultures were still alive and practiced. He saw Senku walk to school and play with a friend. A loud character with brown hair and god-like stamina. He saw someone in the front of a car, driving, saying something about Santa bringing gifts for him. Saw Senku reading old books in the library and in class, all of them about science._

_Then everything went dark for a while._

_Scratch that, things are dark for an insane amount of time._

_He can’t feel anything, nor see, nor taste, or smell, but he can hear counting. It goes on the whole time, the numbers rising in quantity for as long as the darkness prevails._

_There are some wayward thoughts, though. Something about staying awake and constipation? Where some astronaut guy is and what he’s doing. Questions like what the world will look like when he escapes._

_Escapes? Escape what?_

_It does feel like a prison in this darkness. He can’t move, can’t feel, or see or taste or smell. Only thoughts exist in this hellscape._

_Hellscape… Paralyzed…_

Gen abruptly snapped out of the memory spell with a jerk that nearly has him falling over his chair. Only a single word on his mind as his vision adjusted back to normal, and he calmed. 

_Petrification??_

So the kid was telling the truth. But how could that even be possible? Gen was about to ask when he stopped short. The kid was still asleep, sweating profusely and looking highly uncomfortable. Gen sighed and cast a small healing spell, watching as Senku’s features evened out in sleep. 

From there, he turned out the lamps and numbly climbed into his own bed to sleep. Things were going to be very different from then on.

\- - - - - - - - - -

When morning dawned, so did Senku, who seemed just as happy to forget about what the memory spell showed them as Gen was. After eating breakfast, Gen showed Senku around his house. What he could touch, what he absolutely could not touch lest he burn his hand or face off. Their last stop was the library, where Senku was delighted to find his science collection and busied himself all day just reading those dusty old books for hours. He was nearly through half of them by the time Gen was ready to leave. 

Gen hated to go to the city. There was always the chance that someone would recognize him, and then he’d have to shake the magical community off of him again. They were getting more and more desperate with their attacks, which annoyed Gen to no end. He’d already said he wasn’t going to join any groups, for the time being, preferring to be by himself, but no one had listened. 

Gen was almost out of the door, leaving a note on the library door so Senku would know where he was when none other than Senku appeared beside him. 

“Where are you going?” Senku asked. Gen paid him no mind as he secured his bag. 

“The city. I need to get some supplies.”

“Can I go?”

Gen looked down at Senku and his pleading eyes. “When you’re older, maybe.”

“What’re you, my guardian now?” Senku scoffed. 

“Oh, I hope not. But I can’t have you snitching on my identity now, can I?” Gen smirked before moving towards the door. He found himself blocked, however, by Senku leaning against the door. 

“Wouldn’t a child by your side throw your pursuers off because you never had one before and certainly wouldn’t normally have one with you?” Senku asked, innocent to anyone else who couldn’t see the sadistic grin on the kid’s face. 

“How did you know-” Gen stammered, searching for a response. “-that’s not even-” Gen groaned. “-you know what? Fine, I’ll take you. Put this on.” Gen grabbed an extra coat he had, shrinking it down and pulling it over Senku’s head. 

“Ha! You’re not a very good mentalist if you can be persuaded so easily.” Senku teased, making Gen huff. 

“You’re a very blunt child. You know that?” 

Senku shrugged. “I don’t really care.”

Finally, they were ready to go outside and walk through the forest towards the city. As they approached, Gen stopped Senku. “Leave this hood on at all times, okay? No wandering off either, or I’ll put a leash spell on you, got it?”

“Yeah, yeah, don’t leave your sight and stay hidden.” Senku waved him off. “Let’s go!”

Gen chuckled at the kid’s enthusiasm before pulling down his own hood and led him through to the city streets. They made a few stops at the local grocery stands where Gen bought some more food to be able to feed the both of them for a while, while Senku watched on. Then they stopped at some magic stores so Gen could pick up his usual order of supplies and ingredients. Mainly potion bottles and special herbs and roots. 

By the time they were heading back, Senku had gone quiet. The whole day he’d been asking questions and looking around as if trying to find something. It wasn’t until he spoke up that Gen began to understand.

“Is there a library somewhere around here?” Senku asked as he kicked a rock on the sidewalk. 

“Yeah but it only sells spell books.” Gen answered as they walked alone through a few alleys as a shortcut. 

“Are there any libraries that have science books?”

Gen thought for a moment before shaking his head. “Not for centuries.”

“Why is that?” Senku asked, looking up at Gen as he fisted a bit of his cloak to keep up. _He must be getting tired,_ Gen thought. 

“Why use science when magic is easier?” Gen asked him back. 

“Because it’s way more fascinating and satisfying.” Senku grumbled. “Who has all the science books now anyway?”

“Well big collectors and museums still have plenty. I have some, but as you’ve already discovered, not enough to satisfy you.” 

Senku shook his head. “Nothing will satisfy me until I find the origin for the petrification.”

“Was it not a magical event?” 

Senku stopped short, muttering something that sounded like ‘stupid’ under his breath. “Was there magic before the petrification?” He asked, placing his hands on his hips. 

Gen chuckled at the display. “I guess not-”

“Which means it was a strictly scientific event.” Senku nodded, walking again to catch up with Gen, “Any chance we can borrow the museum’s supply?”

“Not unless you’re okay with stealing.” Gen said.

“Tsk okay, I’ll figure something out then.”

Gen sighed before taking hold of Senku’s hand. “Alright, I need to pick up a few more things, but it’s getting late. I’ll drop you back off at the house.”

“Okay.” Senku mumbled tiredly. 

By the time they got back, Senku was more than ready to fall asleep, promptly doing so the moment Gen deemed him clean enough to sleep in the spare bed. Gen blew out the lamps and left the room, stopping only to whisper, “Night, Senku-chan,” before taking off. He had a mission, after all. 

A mission that took so long that by the time he was in the house and everything was ready; it was already dawn. Gen collapsed halfway onto the kitchen counter, leaning his weight against it as his coffee boiled. 

It wasn’t long before Senku came in, rubbing his eyes and sitting in one of the chairs. “Morning,” He mumbled. 

“Morning, guess what I got?” Gen moved to sit in the chair beside him. 

“I’m assuming by those black circles under your eyes that it wasn’t some sleep?” Senku grinned as he teased Gen. 

“Rude.” Gen pouted. “Go to the library. I’m making some coffee.” 

“Whatever.” Senku shrugged out of the chair, slowly walking down the hall and towards the library as requested. 

Gen counted down from 5 as he waited for Senku to make the discovery. Sure enough, he heard Senku’s excited shouts echoing across the hall. 

“Gen! I need to go back to the city!” Senku yelled from the doorway before he took off again. Gen flinched when he heard a stack of books fall and Senku’s excited yelling. “Where do they sell sulfuric acid?” 

_Oh boy._ Gen laughed.

\- - - - - - - - - -

A few years later and they’ve both gotten a new routine together. Senku is growing older and subsequently growing taller, which means more stops to the city for groceries and clothes. But Gen doesn’t mind because the trips are a lot easier with Senku beside him. Meanwhile, Senku helps around the house while doing his science experiments and helping Gen with his magic. 

The house does fill out a bit with all the new stuff they have, though, and as Senku’s experiments get bigger and bigger, he has to move from the library into the kitchen to continue. More than once, Gen has had to stop himself short from drinking out of a cup because it has chemicals in it, but it’s alright. He gets Senku back for using all of his drinking cups by making him do the wash at the river. A hard task with all the stains their clothes get from magical and science runoff. 

Speaking of the two, Senku had been fiddling for a little while with both of their professions, combining his own magic ingredients with chemicals and seeing what they do. Senku called it alchemy and that it was something he read in the old fairytale books they had back in the old days. 

It was an interesting prospect that turns up some surprising results of power. However, sometimes those surprises include waking up to fire smoke coming out of the kitchen and seeing Senku frantically dump water on a cauldron that’s on fire. 

Gen reacted on instinct casting a protection spell on Senku just as a wayward flame nearly singed his weird hair off. 

“Get out of the house!” Gen yelled as he cast another spell around the flame to contain it. Only magic would be able to tame this type of fire, and Senku could not get caught in the crossfire of it. 

“But-” 

“Go, now!” Gen yelled, picking Senku up with his magic and depositing him gently outside. From there, he put all his attention towards putting the fire out. A more difficult task than he thought it would be as the fire kept fighting against him. Born of alchemy, it was like it had a mind of its own. 

By the time Gen did manage to put it out, the sky was dark outside, and he was more than exhausted. 

“Gen?” Senku’s voice called from somewhere behind him. Gen didn’t have enough energy to parse the worry he heard as the ground rushed to meet him. “Gen!” 

It felt more like seconds had passed than hours, but from experience, Gen knew it had been hours already. He groaned as he moved to wipe at his eyes, noticing that he was tucked up in his bed. 

“Easy. Sip this.” Senku said from somewhere at his left as a cup of water was placed in his hand. Gen was grateful, taking big sips at once and then accidentally splashing himself in his hurry to drink more. 

“Sorry- give me a second.” Gen said as he wiped haphazardly at his face. It was then that he noticed his usual robe had been taken off, probably because of all the ash that had gotten stuck on it. 

“Right.” Senku muttered. Gen looked up at him, noticing the resigned expression on his face. If Gen weren’t feeling so tired, he might’ve suspected that Senku felt guilty. “If it’s any consolation, the fire was not part of the plan.” Senku continued, rubbing the back of his neck awkwardly. He definitely wasn’t expecting Gen to burst out laughing. 

“I kind of got that by the girly screaming you were doing, Senku-chan!”

“I was not! Shut up, mentalist!” Senku laughed too, nudging Gen in the shoulder until they calmed down slowly. “Sorry about nearly destroying the house.” Senku wiped at his eyes from all the laughing, getting a pat on his head from Gen. 

“Don’t worry about it. You’re not the only one to have experiments go wrong.” Gen assured as he laid back down on the bed. He was still drained but feeling a lot better, seeing that Senku was okay. “But you will be cleaning everything up while I rest some more.”

Senku smiled as he moved to stand up. “Whatever, mentalist.”

\- - - - - - - - - -

Another couple of years later, and things haven’t changed much between them. Their routine is still the same, and they hold the same schedules, being night owls and all. Gen helps Senku with his experiments when he can, and Senku oversees Gen’s magic practice, and city supply runs. 

The magical community is still trying to come after him but with his protection spells around the house, and the combined abilities of both him and Senku, Gen’s sure everything will be fine. 

And honestly? He’s just having too much fun.

**Author's Note:**

> Here it is! Day 1's continued plot with fantasy au as promised! It took a little while to figure out where I was going with this but I figured I'd just write some fluff after yesterday's angst fest. 
> 
> The beautiful reference for this fic's link! Please check it out :D -> https://twitter.com/Soloorz/status/1310454439929614337
> 
> This is a prequel of day 1's prompt so if you haven't read that, go do that if you want for a continuation! 
> 
> As always, thank you for reading and I hope you enjoyed it!
> 
> Want fic updates? I have a tumblr! @ Widow-Spyder


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